Automatic air gauge



c. E. BRIDGES AUTOMATIC AIR GAUGE Mai-ch 1.6 1926'.-

Fild March-1o, 1925 lll il;

Patented Mar. 16, 1926.

- 1,571,243 PATENT oFFvlcn 'CHARLES E. BRIDGES, or LONG BEACH,y CALIFORNIA.

AUTOMATIC AIR GAUGE.

Applicationled March 10, 1925. Serial N'o. 14,460.

. a citizen of the United States, residing at Long Beach, in the county ofLos Angeles and State of California, have invented new and useful Improvements in Automatic Air Gauges, of which the following is a specification. v This invention relates to automatic air gauges. f Y

An object of the invention is to provide an automatic air gauge adapted to be inter-` posed between a source? of compressed air and a pneumatic tire for the purpose of regulating the air pressure to which the tire is subjected.

A further object is to provide in an automatic air gauge ofthe type rdescribed a plunger adapted to be adjusted to any oneof al given number Vof positions toy predetermine and automatically control the air pressure permitted'to escape into a pneumatic tire. v

Other objects and advantages will be made manifest in the following specification of an embodiment of the invention illustrated in the accompanyingdrawing, in which:

Figure 1 is an enlarged vertical sectional view of the automatic air gauge. y

Figure '2 is a vertical view of the air gauge taken in the direction ofthe arrow 2 of Figure 1, with parts cut away to illustrate the operation of the gauge.'

Figure 3 is a diminished view, partly lin section, of the automatic air gauge in its working relation with a pneumatic tire.

The details of construction and operation of the invention are as follows:

A cylindrical body 1 open at its upper end 2 and provided With a bottom 3 is formed with a suitablev enlargement 4 adjacent the lower end for a purpose hereinafter described.

Adapted to reciprocate within the cylindrical body is a plunger 5 formed with cylindrical ends 6 and 7 adapted to slid- Vably engage the inner walls of the cylin- The cylindrical body is provided with an elongation 10 through which an aperture extends for the accommodation of a dog 12 which has a spring body 13 and is secured to the exterior of the cylindrical body 1 by screws 14. The dog 12 is adapted to engage any one of the notches 9.

A coil expansion spring 15 is disposed within the cylindrical body, bearing at one end upon the cylindrical portion 7 of the plunger 5 and at the other end upon a piston 17 hereinafter described. The piston consists of a block of the cross section illustratedin Figure 1, having acylindrical portion 18 less than the interior of the diameter'of the cylindrical body 1. Interposed'between the cylindrical portion 18 and the cylindrical body v1 is a leather cup washer 19 secured toV the piston 17 by a screw 20. An annular ring 21 is a part `of the piston 17 and is adapted to snugly engage the wall of the cylindrical body 1. Below the ring 21y an annular rshoulder 27 against'which theA washer 4may press when the piston 17 is in a raised position, and when the piston 17 is in a lowered position a chamber 28 is formed.

An air hose 30 carrying air under pressure from a compressor not herein shown is joined to a nipple 31 whichis tapped into cylindrical body 1 adjacent the bottom and communicates with Ythe chamber 28.

Anipple 32 is tapped into the cylindrical body 1 on the side opposite the nipple 31 above the annular shoulder `27. Upon the outer end of the nipple is a standard check tire valve 33 which is adapted to couple with a valve stem 34 of a pneumatic tire.

A scale 35 designating the pound pressure controlled by each notch 9 is properly placed on the-plunger 5. It is obvious that the scale 35 must be computed with referencek to the determined tension of the spring 15.

In the use of the invention the plunger 5 is adjusted so that the number of pounds pressure it is desired to inject into a tire 3U appears by the scale adjacent the dog l2 and the spring action ol the epring` body 13 will tend to hold the dog,r in engagement with the notch 9 against the pressure of the coil SDring l5. The standard cheek tire ralve 33 is then coupled with the ralre stem lll: ol the tire 3G. The piston ',tT is normailtv retained in its upper position aa indicated in Figure by air pressure from the hose on the lower end ol piston lt', and itt the pressure in the tire t be lens than the predetermined preasure indicated by the scale the air pressure in the lower part ot the chamber will by connuunieation with the tire be lesa than the pressure et' the spring lo which will immediatelyY prees` the piston 1T dewnwardly until it rests on the bottom whereupon mnnpreaned air trom the hose. It() will enter the chamber 2h arnl encirclingr the piston iT willbe diachar y'ed through the nipple 2 and the stan( checl: tirel ralre til into the tire ,lt. Chen the pressure Within the tire lfl heroines equal te the predetermined pre-teure exerted by the spring t5 upon the piston l? the reaction ot the air pressure from the tire will cause the piston 1T to rise until the washer 25 is coinpressed against the annular shoulder 2T ol the cylindrical bodyv l, thus prerenting tur ther discharge ot comprcased air into the tire Sti. lt" will be apparent that the cheek tire valve 32:5 will retain pressure within the nipple 232 and the lower partv ot the chainber so that as lone' as the air pressure in the lower part ol' the chamber is' equal to the pressure exerted by the sp1-ingr lo the entrance ot compressed air through the hose 30 int'o the upper part ot' the chamber will have no etieet' on the movement ot the pieton 1T.

lt is obriouaA that the air pressure troni the hose 3l will automati 'ally raiee the pie ton li' to its upper position when the cheek tire valve 33 in closed, a. seal between the piston and the cylindrical body l beingr effected by the leather cup washer ttt.

Varioue` changes majv be made without departing trom the spirit ot the invention as claimed.

That is claimed ie:

l. An automatic air gauge lor inllatingi pneumatic tires, comprising,r an elongated cylinder haring an internal bore, a recess of larger diameter than the bore formed in one end thereof, an air inlet in the base ot the recess, an air outlet in the lower end ot the cylinder above the recess` a piston haring a pair of heads, one ot' said heads4 being larger than the other, with the larger head within the recess and the smaller head within the bore of the cylinder, a plunger haring a pluralityv ot annular grooves slidably mounted in the bore of the cylinder, an expansion springP between said plunger and piston and a dogg formed ot" material having;r one end secured to the ev inder and the other end adapted to engage the annular groove in said plunger.

An automatic air gauge adapted to be interposed between a source ot compressed air and a tire valve comprising an elongated cylinder haring; a bore and an internal annular recess toi-med at the lower end there.- ot', an air inlet entering;- the recess at the lower end, an air outlet formed in the lower end of the bore above the recessT a piston haring a head Slidable in the bore ot' the said cylinder and a second head ot lare-er diameter than the lirstz head but ot smaller diameter than the internal recess', adapted. to normally rest on the bottom et. the rez-esa, the said piston haring an annular :space he tween the said heads, a plunger haring; a plurality ot' annular grooves alidahlj7 mounted in the bore of the cylinder7 an eis panelen coil spring' within the bore of the cylinder between the plunger and the piston, a dog formed of springr material adapted to engage the annular grooves in the said plunger and retain the plunger in predeten mined position, the said pieten being adapted to be raised when the air pressure in the tire is sufficient to overcome the. tension ot the said spring.;l and the large head oli the piston being adapted to engage thel upper tace of the recess and out oill the air entering through the inlet.

In testimony whereot l have signed my name to this specification.

CHARLES E. BltllXlES. 

